#include <stdio.h>
#include <math.h>

int main()
{
	double H,S1,V,L,K,n; 
	double t1, t2, i, i1, i2; 
	int res = 0; 
	scanf("%lf %lf %lf %lf %lf %lf", &H, &S1, &V, &L, &K, &n); 
	t1 = sqrt(H/(10*0.5));
	t2 = sqrt(fabs(H-K)/(10*0.5));
	i1 = S1 - t1*V; 
	i2 = S1 - t2*V + L;
	
	for (i=0.0; i<n; i += 1.0) {
		if ((i-i1+0.0001)>0.0 && (i-i2-0.0001)<0.0) {
			res ++; 
		}
	}
	printf("%d\n", res); 
	return 0; 
}


